<script lang="ts" setup>
import { reactive, ref, watch } from "vue";
import { useMouseInElement } from "@vueuse/core";

const images = [
  "https://yanxuan-item.nosdn.127.net/a6939f41c48fa9e9c8f7a7ed855351f1.jpg",
  "https://yanxuan-item.nosdn.127.net/0cdfd546f8675669b87716114ad5900a.jpg",
  "https://yanxuan-item.nosdn.127.net/240983ccc935146a4795e3990d30468d.jpg",
  "https://yanxuan-item.nosdn.127.net/d46e005025a5d3b73c4781d31b327558.jpg",
  "https://yanxuan-item.nosdn.127.net/330913911087b44b0d817dd78233165f.png",
];

// 当前预览图的索引
const currIndex = ref(0);

// 1. 是否显示遮罩和大图
const show = ref(false);
// 2. 遮罩的坐标(样式)
const layerPosition: any = reactive({
  left: 0,
  top: 0,
});
// 3. 大图背景定位(样式)
const largePosition: any = reactive({
  backgroundPositionX: 0,
  backgroundPositionY: 0,
});
// 4. 使用useMouseInElement得到基于元素左上角的坐标和是否离开元素数据
const target = ref(null);
const { elementX, elementY, isOutside } = useMouseInElement(target);
watch([elementX, elementY, isOutside], () => {
  // 5. 根据得到数据设置样式数据和是否显示数据
  show.value = !isOutside.value;
  // 计算坐标
  const position = { x: 0, y: 0 };

  if (elementX.value < 100) position.x = 0;
  else if (elementX.value > 300) position.x = 200;
  else position.x = elementX.value - 100;

  if (elementY.value < 100) position.y = 0;
  else if (elementY.value > 300) position.y = 200;
  else position.y = elementY.value - 100;
  // 给样式赋值
  layerPosition.left = position.x + "px";
  layerPosition.top = position.y + "px";
  largePosition.backgroundPositionX = -2 * position.x + "px";
  largePosition.backgroundPositionY = -2 * position.y + "px";
});
</script>
<template>
  <div class="goods-image">
    <!-- 大图 -->
    <div
      v-show="show"
      class="large"
      :style="[{ backgroundImage: `url(${images[currIndex]})` }, largePosition]"
    ></div>
    <!-- 中图 -->
    <div class="middle" ref="target">
      <img :src="images[currIndex]" alt="" />
      <!-- 遮罩色块 -->
      <div v-show="show" class="layer" :style="layerPosition"></div>
    </div>
    <!-- 小图 -->
    <ul class="small">
      <li
        v-for="(img, i) in images"
        :key="img"
        :class="{ active: i === currIndex }"
      >
        <img @mouseenter="currIndex = i" :src="img" alt="" />
      </li>
    </ul>
  </div>
</template>

<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;
  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }
  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move;
    img {
      width: 100%;
      height: 100%;
    }
    //cursor: pointer;
    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, 0.2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }
  .small {
    width: 80px;
    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;
      img {
        width: 100%;
        height: 100%;
      }
      &:hover,
      &.active {
        border: 2px solid #27ba9b;
      }
    }
  }
}
</style>
